Insulation-piercing electric terminal



Aug. e, 1957 2,802,195

R. MARTINES INSULATION-PIERCING ELECTRIC TERMINAL Filed Dec. 9, 1954 .l /i 89 @@SQEEQEQ@Wg@ O QQQOO @Op O /g /lf 3/ INVENT.

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ATTORNEYS,

nited States Patent 2,802,195 INSULATION-PIERCING ELECTRIC TERMINAL Rene Martines, Warwick, Rl'. I.

Application December 9, 1954, Serial No. 474,650

3 Claims. (Cl. 339-276) This invention relates to an improvement in an insulation piercing electric terminal.

An electric terminal of the above character in common use in the trade is formed with a `channel for receiving an insulated covered wire conductor.- Two prongs are provided in the bottom of the channel so that the prongs will pierce the insulation and engage the wire core of the conductor to make electrical contact therewith when the side walls thereof are folded over the conductor. The prongs which are generally triangular in shape are formed by making V cuts through the bottom wall of the channel and pushing out and bending the partially severed stock so that it will extend at substantially right angles to the said bottom wall. This leaves an opening in the bottom wall at each prong through which moisture will pass along the prong to cause corrosion thereof and thus `destroy the electrical contact between terminal and conductor wire.

An object of this invention is to provide an electric terminal of the above character having the insulation piercing lance thereof formed in a manner to be sealed to atmosphere.

Another object of this invention is to provide an electric terminal of the above character having the insulation piercing prong or lance thereof raised from the stock without piercing the stock.

A more specific object of the invention is to form a terminal of the above character with a plurality of insulation piercing lances formed by a rst step of drawing the stock in a form adapted to be subsequently pressed into an insulation piercing lance.

With these and other objects in view, the invention consists of certain novel features of construction as will be more fully described and particularly pointed out in the appended claims.

In the accompanying drawings:

Figure 1 is a plan View of an electrical terminal embodying my invention.

Figure 2 is a sectional view on an enlarged scale taken substantially along line 2 2 of Figure 1;

Figure 3 is a plan view Shown on an enlarged scale of the terminal shown in Figure l with the conductor omitted; v

Figure 4 is a view similar to Figure 3 showing the opposite side of the terminal;

Figure 5 is a perspective view on a very large scale of a fragmentary portion of the terminal showing the lance in the process of being formed;

Figure 6 is a similar view showing the lance after a further operation thereon;

Figure 7 is a sectional view taken substantially on line 7--7 of Figure 5;

Figure 8 is a sectional view taken substantially on line 8 8 of Figure 6; and

Figure 9 is a sectional view taken on line 9-9 of Figure 2; and

Figure 10 is a plan view of a tlat strip of material show- PatentedrAug. o, 'iat-i7 2 v ing the various steps in the sequence performed on the strip to arrive at a n'nished terminal.

rthe terminal 10 shown in tne drawing is a spade type having a wire receiving, channel i1, the sides of which are provided with arms 12, v12' for rolding'and crimping about an insulated conductor 13 positioned in the said channel 11. A plurality or lances 14 are formed in the bottom wall of the channel, and these are adapted to pierce the insulationon the conductor 13 and engage in electrical contact with the wire core 15 of the conductor. The terminal is made of a single piece of suitable sheet material and usually in strip form in a manner to be hereinafter described wherein each terminal as attached to the other and individually severed from the strip during machine attachment of the conductor 13 thereto. '.lhe terminal may, of course, be supplied separately and manually attached to conductors in the known manner.

The lances 14vareformed in the sheet material prior to the formation-ofthe-channel 11. To this end a hollow conical protuberance 16 is first drawn from thev sheet stock 17 in the at condition thereof (see Figures 5, 7, and l0). This is accomplished by means of a so-called drawing operation bythe use of tools well known in the art. 'lhe protuberance 16 is next subjected to a pressing operation to flatten the protuberance in a pointed conical like formation 18 (see Figures 6, 8) generally elliptical in cross section and having a sharpV rounded chisel end 19 which is adapted under pressure of crimping the arms 12 about the conductor 13 to pierce theinsulation 20 thereof and be embedded in the wire core 15.

In making the terminal 10 in strip form, the various steps of operation involved may be conveniently carried out by means of a usual tool press which may be equipped with the proper tools to perform various combined operations. These operations are preferably performed simultaneously at different stations on the sheet material 17, which operations, when combined, will form a complete terminal attached to the strip in some manner for subsequent severing therefrom as used. The various steps or operations are illustrated in Figure l0 in a preferred sequence which may be altered in part depending upon conditions and equipment available. The strip is advanced from left to right from a supply (not shown) in steps a distance equal to the width of the terminal. By a punching and/ or the like operation, the strip is first pierced with a generally rectangular opening 26 inwardly of the upper marginal edge portion 27 of the strip as viewed on the drawing. The supporting structures of the tools employed determines to a degree the spacing between operations, and thus each tool may perform a plurality of like operations prior to the initial portion of the strip operated thereon having been advanced to a position to subject the strip to a next different operation. Thus, the strip illustrates a plurality of each of the several operations ma-de on the strip. Since such plurality of operations are merely the result of tool spacing, the description of the various different operations will follow the sequence in which they are made. It will be understood that a complete finished terminal will be made at each cycle of operation of the machine.

The strip is fed through the machine step by step, and at the second station the strip is pierced with a second opening 28 of generally triangular shape with the base thereof extending parallel with the edges of the strip and the apex thereof extending midway between adjacent openings 26. The strip is next severed crosswise thereof along line 29 which extends from the apex of opening 28 to a point substantially in line with the upper edges of adjacent openings 26. It may now be observed that the spade ending 30 of the terminal is defined by the slits 29 and the adjacent edges of openings 28. At the station at which the slitting operation takes place, the lances 14 may be simultaneously initially drawn into the conical protuberance 16 (see Figures 5-8). The strip is shown as being face down, which shows the protuberances in bottom plan, Reference to Figure 5 and prior description may be referred to asY to thesequence of operationsin making lance 14. The attening of the protuberance 16 may be made in several stagesof operation in order to arrive at the shape shown at Figure 6. The strip is next severed along line 31 which extends from the lower edge of the strip to intersect the base of triangular opening 28 to sever the strip at this location, and `the severing is of a shape to form the arms 12Mon o ne side of a terminal and the opposite arm 12 on the next terminal to be made. As seen at 32, the complete blank for the terminal 10 has been made and is attached to the marginal edge 27. At the next and last station, by a bending operation the arms 12, 12 are bent outwardly in 4general U`shape to form therebetween the wire receiving channel 11. The terminal 10 may be severed from the strip by cutting along the broken lines 33. This is usually done in a known manner during the machine operation of attaching the terminal to the conductor.

It will be apparent `that the lance 14 formed as above described has a yrelatively wide base 22 from which the lance tapers upwardly to the chisel edge 19 as compared to a pointed end or prong of the prior art. Further, such chisel edge is more adapted to dig in and be embedded in the wire core 15 and provide a much greater area of contact with the core 15.

I claim:

1. An electric terminal having an insulated electric conductor-receiving channel with arms at either side thereof, a hollow lance Aof the same stock as said channel in the bottom wall of said channel, said lance having a conical formation with continuous walls generally elliptical in cross section to provide a large contact area, the hollow portion opening on the opposite wall of said channel, said lance being adapted upon folding and crimping the arms of the channel about the said conductor to pierce the insulation of the conductor and embed in the wire core thereof.

2. A terminal as in claim 1 wherein the major axis of the elliptical cross section is parallel to the longitudinal extent of said channel.

3. An electric terminal having an insulated electric conductor receiving channel with arms at either side thereof, a hollow lance of the same stock as said channel in the bottom wall of said channel, said lance having a conical formation with continuous walls generally elliptical in cross section terminating in a chisel end to provide a large contact area, the hollow portion opening on the opposite Wall of said channel, said lance being adapted upon folding and crimping the arms of the channel about the said conductor to pierce the insulation of the conductor and embed in the wire core thereof.

References Cited in the tile of this patent 

